1. Field
The following description relates to a receiving device including a plurality of reception antennas, and more particularly, to a technology that may maximize a diversity gain, while reducing or eliminating a multi-path interference (MPI).
2. Description of Related Art
Researches have been conducted to provide various multimedia services that support a high quality and a high data transmission rate, in a wireless communication environment. As part of the research, a technology related to a multi-input multi-out (MIMO) system that uses a plurality of channels in a spatial area has been developed.
The MIMO technology uses multiple antennas to increase a number of channel bits in a limited frequency resource, and provides a high data transmission rate. The MIMO technology uses multiple transmission/reception antennas in an environment where one or more scatterers exist, to provide a channel capacity proportional to a smaller number of antennas, between the transmission antennas and the reception antennas.
In the MIMO communication system, a plurality of channels exist between a transmitting device and a receiving device. As an example, when a number of antennas of the transmitting device and a number of antennas of the receiving device are four, a received signal Y may be expressed as given in the exemplary Equation 1 below.
                                                        Y              =                            ⁢                              [                                                                                                    y                        1                                                                                                                                                y                        2                                                                                                                                                y                        3                                                                                                                                                y                        4                                                                                            ]                                                                                        =                            ⁢                                                                    [                                                                                                                        h                            11                                                                                                                                h                            12                                                                                                                                h                            13                                                                                                                                h                            14                                                                                                                                                                            h                            21                                                                                                                                h                            22                                                                                                                                h                            23                                                                                                                                h                            24                                                                                                                                                                            h                            31                                                                                                                                h                            32                                                                                                                                h                            33                                                                                                                                h                            34                                                                                                                                                                            h                            41                                                                                                                                h                            42                                                                                                                                h                            43                                                                                                                                h                            44                                                                                                                ]                                    ⁡                                      [                                                                                                                        x                            1                                                                                                                                                                            x                            2                                                                                                                                                                            x                            3                                                                                                                                                                            x                            4                                                                                                                ]                                                  +                                  [                                                                                                              n                          1                                                                                                                                                              n                          2                                                                                                                                                              n                          3                                                                                                                                                              n                          4                                                                                                      ]                                                                                                        =                            ⁢                              HX                +                N                                                                        [                  Equation          ⁢                                          ⁢          1                ]            
In this example, the symbols x1, x2, x3, and x4 are transmission symbols, hab is a channel coefficient corresponding to a path until a bth transmission symbol reaches an ath receiving antenna, and n1, n2, n3, and n4 are noise.
The receiving device separates a received signal into a plurality of streams and performs detection. The streams, for example, the transmission symbols, transmitted from the transmitting device are difficult to accurately detect when multi-path interference (MPI) exists.